The present invention relates to a photographic printer, and more particularly to a printer-processor which can make different sizes of prints.
Various types of photographic printer-processors are known which can make a large number or prints easily. Such printer-processors, which are found in many processing mini-labs, primarily comprise a printing section, a processing section, and a cutter unit.
The printing section is provided with a light source for illuminating an original film, such as a negative or a reversal film, held by a negative carrier. The printing section also includes an exposure system, including at least a printing lens and a shutter, for projecting an image of an original film frame onto photographic paper which is placed at an exposure station, so as to form a latent image on the photographic paper.
An image recorded on the original film may be measured by equipment such as an optical scanner to detect the intensity or the amount of light passed therethrough, in accordance with which proper exposure may be determined automatically. Exposure may be repeated one or more times consecutively for each frame of the original film in order to make a large number of prints.
The exposed photographic paper is cut by a first cutter to a predetermined length usually sufficient to include a plurality of image frames, and is transported to the processing section of the printer processor for continuous processing, including the steps of developing, bleaching-fixing and washing or rinsing. The exposed and processed photographic paper then is cut to a predetermined length by a second cutter in the cutter unit to provide individual prints framed by white margins.
Meanwhile, as is well known in the art, there are various types of printer-processors which use a plurality of interchangeable printing lenses having different focal lengths or printing magnifications in order to make different sizes of image frames for prints. These printing lenses are interchangeably mounted on a lens mount of the printer-processor so that the exposure axis (which, in this specification, is a straight line connecting the centers of a printing lens and an image frame projected by the printing lens) of each printing lens coincides with the optical axis of the printing lens which is perpendicular to a plane onto which an image of an original film is projected. Exposure aperture size and the length of photographic paper advancement or withdrawal are changed in accordance with a change in print size.
The printer-processor is provided with a stationary cutter disposed after the exposure station, adjacent to the exposure aperture, for cutting off an exposed part of the photographic paper. A problem associated with printer-processors with stationary cutters is different widths of end margins formed when different sizes of prints are produced.
As shown in FIG. 1, when printing a large size image frame (hereinafter referred to as an L-size image frame and which has a diagonal length twice as long as that of a small size, or S-size image (frame) on a web-like photographic paper P, a plurality of L-size image frames L.sub.1, . . . , L.sub.n-1, L.sub.n are printed consecutively with a margin R of width 2M left between adjacent L-size image frames. After the Nth L-size image frame Ln has been exposed, the exposed photographic paper P is cut off by a cutter C along a cutting line CL, leaving an end margin RL of width M along the rear edge thereof. The exposed photographic paper then the separated from the unexposed photographic paper P. This exposed part of the photographic paper P is continuously processed from developing to rinsing in a processor, dried by a dryer, and then cut off by a cutter unit into L-size image frame prints with front and rear margins M left on both ends.
When making more L-size image frame prints, either from the same original film or from another original film, the same printing and processing operations may be repeated without any need for adjustment of elements of the printing section. Cutting of the photographic paper generally is carried out in accordance with information relating to a predetermined number of prints, and the size of each frame.
One type of problem which can arise during operation of a printer-processor as described above occurs when a different size of print is desires. For example, if S-size image frame prints are needed after L-size image frame prints, as is shown in FIG. 1, between the first S-size image frame and the front edge of the photographic paper P or the cutting line CL, there is left a margin Rs which is quite a bit wider than the ordinary width M. This is because, while the print size has been changed, the printer-processor has not adjusted its advancement operation to compensate accordingly.
To prevent recurrence of such a wide margin, the withdrawal length or advancement length of the photographic paper is changed and printing then is resumed, starting with the second S-size image frame S.sub.2. Specifically, the advancement length of the photographic paper is changed to the total length of the length of one S-size image frame and the ordinary widths (2M) of front and rear margins.
After exposure of the last S-size image frame S.sub.n, the photographic paper P is automatically advanced by the changed length and then is cut by the cutter C. However, as is apparent from FIG. 1, because of the excessively large initial margin Rs, a rear part of the last S-size image frame S.sub.n is cut off along a double dotted line CL by the cutter C, resulting in a defective, shortened print. In order to prevent such a defective print, it is necessary to advance the photographic paper excessively after the exposure of the last S-size image frame S.sub.n.
As described above, in conventional printer-processors, there is a problem that, when printing a plurality of S-size image frames, unnecessarily width margins are left along the front and rear sides of the exposed photographic paper. Therefore, when making S-size image frame prints after L-size image frame prints, a manual operation to take an unnecessary front margin away from an exposed part of the photographic paper has to be conducted in order for the cutter unit automatically to cut and separate the printed photographic paper into individual S-size image frame prints. Such a manual cutting operation is troublesome when the printer-processor is automatically making a large number or prints. Further, the unnecessary margins are wasteful and result in a great amount of wasted, unused photographic paper,
In order to avoid such a waste of unused photographic paper, after the exposed photographic paper has been cut off from the major part of the photographic paper after having exposed all of the L-size image frames L.sub.1, . . . , L.sub.n-1, and L.sub.n, the photographic paper P is moved back by a predetermined length in order to avoid an unnecessary margin in the first S-size image frame S.sub.1. When the photographic paper P is cut off by the cutter C for every exposure of S-size image frame, the photographic paper P has to be moved back by the predetermined length for every exposure and cutting. Furthermore, in any case, when cutting the exposed photographic paper R after in exposure of the last S-size image frame S.sub.n, the photographic paper P has to be forwarded additionally to be cut with a proper margin in the last S-size image frame S.sub.n.
As described above, in conventional printer-processors, it has been required to move the photographic paper back before exposing the first S-size image frame or move the paper forward an additional amount after the exposure of the last S-size image frame S.sub.n, when making a plurality of successive S-size image frame prints. These operations also are required in making S-size image frame prints one by one. To enable reverse movement or additional advancement of photographic paper, it is necessary to provide an advancing mechanism, with its associated mechanical elements, for reversing and additional advancing of photographic paper as well as for normal advancing of the photographic paper. Such a photographic paper advancing mechanism unavoidably becomes complicated and results in inconsistent advancement of photographic paper.